The objects in the mirror are closer

The objects in the mirror are closer than they look – this information is a proven true safety warning that has been reminding drivers for decades that the field of view reflected by the rearview mirror is slightly different from reality. Despite its limitations, the mirror is still an important device in the car, helping the driver to turn around or change lanes. However, today's advanced driver assistance system (ADAS) transcends the reflection of the mirror and provides the driver with an extended viewing angle based on the driver's seat.

The Camera Monitoring System (CMS), also known as an electronic mirror or smart mirror, is designed to provide a mirror experience in the form of a camera and display. Imagine looking at the rearview mirror display and you can see the panorama behind the car. When you look at the side view mirror, you will see a high-resolution displayLCD MONITOR ARM Manufacturers  that shows the vehicle next to you. These scenarios are becoming a reality, and other features such as blind spot monitoring systems and parking assistance systems are also becoming a reality.

It is important to understand the current transition from car mirror to CMS. It is not surprising that ADAS functions have been used in car mirrors in today's vehicle systems. In the past decade, new cars have added a camera to the rear of the vehicle, or installed the camera on an existing rearview mirror and installed a display in the car to provide the driver with rear or side views of the vehicle. Different perspectives.

How does the camera monitoring system expand the driver's field of vision?

The side mirrors are different because the camera is on the car mirror. The side view mirror is still used for viewing, but in general, the camera will only work when the driver turns on the directional light or reverses. During a turn or lane change, the camera outputs a video transmission to the infotainment display on the dashboard and may display a slightly different angle than the side mirror itself, as shown in Figure 2.

How does the camera monitoring system expand the driver's field of vision?

The current CMS configuration using a combination of a mirror and a camera and display has been described. It is worth noting that CMS rearview mirror replacement can be achieved by installing one or two cameras at the rear of the vehicle.

From the rear of the vehicle, the video data from the imager is input to TI's DS90UB933 parallel interface serializer or DS90UB953 serializer with Camera Serial Interface (CSI)-2. The data is then serialized to a DS90UB934 or DS90UB954 deserializer via a Flat Panel Display (FPD)-Link III coaxial cable and output to the application processor for video processing (eg JacintoTM TDAx processor) and then displayed in the rearview mirror display. On the screen. If the display is away from the Jacinto application processor, the display interface serializer and deserializer are required to route the data over the coaxial cable again. You can use the DS90UB921 and DS90UB922 Red Green Blue (RGB) format serializers and deserializers separately, or, if you want to apply a higher resolution display, you can use the DS90UB947 and DS90UB948 Open Low Voltage Differential Signal Display Interface (LDI) Device.

Figure 3 shows the connections between these devices when using the onboard display of the application processor.

How does the camera monitoring system expand the driver's field of vision?

The second CMS is the side mirror replacement section. The camera must be in the same position as the original mirror. The video data of the camera shows the angle of view seen by the driver in the mirror. To do this, the camera data is serialized and sent via the FPD-Link III coaxial cable to a remote display located in the upper door or in the rearview mirror display. With the camera and display, the side view now gives the driver a more direct line of sight. For example, if the rearview mirror contains a side view and a rear view display, the driver only has to look at one location.

Another option for side mirror replacement is to add a second camera that is in the same position as the camera at different viewing angles. The advantage of this setup compared to standard mirrors is that with two cameras at different angles, one camera can be used to provide a side view angle, while the second camera can provide a wider range for blind spot detection and collision alerting. Vision. Figure 4 shows the dual camera side view mirror replacement system.

How does the camera monitoring system expand the driver's field of vision?

Now you may ask, if the driver can achieve of the same functions through the mirror, then why do they need a camera and display. The answer is that the camera can provide functionality separately through the car mirror. If there is only a side view mirror, avoiding side collisions is entirely up to the driver. Through the camera, potential collisions can be detected before the lane change, and then the vehicle warning alarm is activated to prevent the driver from making unwise behavior. A panoramic rear view with a wide field of view (FOV) rear view camera or a separate narrow focus rear view camera provides the driver with a different line of sight and reduces or eliminates blind spots that cannot be found using the mirror alone.

But this is only the beginning. In order to move the vehicle from the driver assistance system to the autonomous system, the CMS can be integrated into the sensor fusion system. CMS may be combined with ultrasound or even radar. The combination of rear view and side view cameras and ultrasound can assist the driver when parking, or even stop. Radars combined with rearview mirrors provide additional protection against lane changes and avoiding side collisions.